Sequential channeling in Node Editor (no PBR workflow)
You can use &quot;texture coordinate&quot; input node and a &quot;color ramp&quot;.
The X output is between 0 and 1. So if we split the color ramp in three constant steps at 0, 0.3333 and 0.6666 we'll have the color we want for the good disk.
For the grey part, we just compare the input value (0, 0.1, 0.2, 0.3) to X clamped into 0 and 0.3.